Vehicle emissions standards generally are being closely examined worldwide by regulatory environmental groups. Standards are being set to lower and lower various types of emissions. Specifically, vehicle particulate emissions limits are being significantly reduced. This includes limits for particulate emissions from gasoline/spark-ignition engines as well as other engine technologies.
In spark-ignition engines, the reduced limits for particulate emissions are solved in part with improving a vehicle hardware design. Attention is being given to injection technology to improve combustion. If not optimized, for instance, injector coking can lead to unfavorable fuel spray and increased particulate emissions. Therefore, technology is evolving to improve hardware performance in order to reduce particulate emissions.
Emissions such as particulate emissions are measured in traditional driving cycle tests; however, these traditional tests do not sufficiently replicate real-world driving conditions. Therefore, traditional test results may not be representative of a vehicle emissions during real-world driving.